Control for a fuel supply system



March 8, 1960 D. c. BREEDING CONTROL FOR A FUEL SUPPLY SYSTEM Filed Oct. 25, 1956 Aug/Eur Ana/Mr- A/R PRESSURE 31E i g TEMRERA TURF vDEW-5 T FLUX TIME DAVID C. vBREEDING.

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United States CONTROL FOR A FUEL SUPPLY SYSTEM David C. Breeding, South Bend, Ind., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application October 25, 1956, Serial No. 618,363 i 5 Claims. Cl. 123-119 The present invention relates to a control for a fuel supply system wherein the quantity of fuel supplied to an engine is controlled by varying the time duration of fuel valve opening. A fuel supply system of this type isdisclosed and claimed in US. application Serial No. 567,688, filed February 24, 1956, and assigned to the assignee of the present invention and now abandoned. v

In an embodiment of the control of my invention a transformer is periodically energized as a function of engine speed to produce for a controlled time duration an output voltage of alternate polarity. The output of the transformer is used to bias an amplifierinto co'nduc-.

tion for the time duration of transformer voltage output;

The amplifier in conjunction with a distributor succe s-' sively energizes the fuel valves in timed relation to the:

periodic energization of the transformer.

It is an object of my invention to provide a control for a fuel supply system having simple construction with few moving parts. 7

It is a further object of my invention to provide a compact, light weight reliable control for a fuel supply system. I

Other objects and advantages of my invention will be readily apparent from the following detailed description taken in connection with the appendeddrawingsin.

which:

Figure l is a diagrammatic illustration of a control for Patented Mar. 8, 1960,

. 2 flux relationship in transformer T is given by the following equation:

. Et=2BAN10-' where:

E=voltage i=tlm6 B'=fiux density A=core area N=number of turns of the inductor In a given installation B, A and N are constant and may be represented by K.

Therefore:

Thus by varying the voltage applied to the primary inductor 12 by means of potentiometer 10 the time for the'fiux in core 14 to change from saturation in one direction to the saturation in the other direction may be controlled. The core 14 is constructed of high retentivity material so as toproduce a substantially square loop hysteresis curve as characteristically shown in Figure: 2. As to be noted in Figure 2 when the current is reduced to zero as when wiper arm 22 breaks contact with contact. 20 there is substantially no change in flux so there is substantially no surge of back in the inductor. A secondary inductor 26 is wound on core 14 sothat when the current flows in the primary inductor a voltage will be, induced in the secondary while the flux is changing. A

- characteristic curve of the induced voltage in the second-:

...prising resistances R R ary for a given applied voltage to the primary is showm in Figure 3. The width or time duration of the induced. voltage pulse may be accurately controlled by variation by'suitable means, of the applied voltage to the primary...

In a preferred embodiment amplifier A is a transistorhaving first, second and third control elements. In the: embodiment now described, the emitter or control ele-. mentis connected to the source E and to ground or a... reference potential at 28 through a voltage divider com- The values are selectedso that amplifier A is biased in a normally non-conductive state. The emitter is connected through resistor R to a center tap of secondary inductor 26. The base of amplifier A is connected through current limiting resistor R and a pair of one-way conductive devices or diodes 30 and 32 tentiometer 10 to a center tap of primary inductor 12 which is wound on a relatively high retentivity core 14' of transformer T. Potentiometer 10 is variable in re sponse to an engine operating condition such as engine temperature, ambient temperature, relative humidity, ambient pressure, induction passage pressure, exhaust temperature and/or pressure or mass air flow or a combination thereof. The ends of primary inductor 12 are respectively connected to rings 16 and 18 which are alternately connected to successive segmental contacts 20. A wiper arm 22 mounted on a shaft 24 which is adapted for rotation as a function of engine speed is adapted to successively engage contacts 20 whereby the ends of the primary inductor are alternately connected to ground or reference potential at 28. The effect of successive engagement of wiper arm 22 with contacts 20 is to cause current to flow in one direction in portion 12a of primary inductor 12 and then in the opposite direction in portion 12b of primary inductor. Thus when current is flowing in portion 12a core 14 is saturated in one direction and when current is flowing in portion 12b the core is saturated in an opposite direction. The voltage, time and number of valves V may conveniently correspond to the number of combustion chambers in the engine to which the fuel supply system is adapted to supply fuel. It is to be understood, however, that the proportion of valves V to combustion chambers may be increased or decreased as desired. Solenoids 34a, b, c, d, e, f, g and h are respectively connected to contacts 36a, b, c, d, e, f, g, and h in switch S by an appropriate wiring harness (not shown). Wiper arm 22 is adapted to successively engage contacts 36a, b, c, d, e, f, g and h in timed relation to the engagement of the arm with contacts 20 whereby the solenoids 34a, b, c, d, e, f, g, and h are successively connected to ground or reference potential at 28.

In operation a voltage from source E is applied to primary inductor 12 the magnitude of which is varied as a function of engine operating conditions by a potentiom' eter 10 or other suitable means. Switch S causes the current to flow first in one direction and then in the opposite direction whereby the primary inductor is periodically energized to saturate core 14 of transformer T first in one direction and then in the opposite direction. The time required for the flux of core 14 to change from saturation in one direction to saturation in the other direction is controllable by varying the magnitude of voltage applied to the primary inductor. The time required for the core to be saturated in one direction from a conditiorrof saturation in the other direction determines the time duration of induced voltage in the secondary induotor 26. A portion of the induced voltage in the secondary is applied to the base of amplifier A and is of sufficient magnitude to cause amplifier A to conduct for the. time duration that the induced voltage is applied to. the. base. When the amplifier A is conductive, current flows from the emitter to the base through resistor R and de,-.

pending upon the polarity of the induced voltage in secondary inductor 26 through an appropriate one-way conducted device 30 or 32. Because of the pair of one-way conductive devices the amplifier A willconduct irrespective of the polarity of induced voltage in secondary inductor 26. This arrangement permits continuous periodic operation of the control without resort to a resetting device to return the flux in core 14 to a reference value so as to obtain a uniform polarity. When amplifier A is conductive, current flows from the collector to ground successively through solenoids 34a, b, c, d e, f, g and h and respective contacts 36a, b, c, d, e, f, g and h and wiper arm 22.

While only one embodiment of my invention has been. described it will be readily apparent to those skilled in the art that various changes and arrangements can be made to attain the objects of the invention without departing from the spirit thereof.

A I claim:

1'. A control for a fuel supply system, C IQP' 'iSing an inductor, means for periodically inducing a voltage said inductor; of alternate polarity, means independent of said first mentioned means for controlling the time duration that said voltage is induced, an amplifier normallybiased to a, non-conductive stage. and means including voltage polarity control means connecting said inductor. to. said: amplifier for biasing said amplifier into conduction d'ur ingt he time duration that said voltage is induced.

2 A control member for a fuel supply system having a plurality; of electrically actuable valves, comprising: an inductor, means for periodically inducing a voltage insaid inductor of alternate polarity, means independent of said; first mentioned means for controlling, the time duration. that said. voltage. is induced, an. amplifier nor.- nially biased to a non-conductive stage, means including voltage polarity control. means connecting, said inductor'i tojsaid' amplifier for biasing said amplifier into conduction during the time duration thatsaid voltage isinduced, a circuit; including means actuable; in timedf relation to said first-mentionedmeans for periodically connecting, saidamplifi'er to ground through'successive' valves; i

3;. A control for a fuel supply'system for an internal combustion engine having an electrically actuable fuel control membercomp'rising a core, primary and second ary inductors wound on said core, variable voltage means responsiveto changes in an engine operating condition connected to said primaiy inductor for saturating said nd and third. control elements, means connecting said first element to said secondary inductor intermediate the ends thereof, means including one-way conductive devices connecting the ends of the secondary inductor to the second control element, and means connecting the third element. to said, member.

4. A control for a fuel supply system for an internal combustion engine comprising a core, a primary inductor mounted on said core, a source of voltage variable in response to changes in an engine operating condition, means connecting said source to said primary inductor intermediate the ends thereof, means synchronized with said v engine for alternatively connecting the ends of said primary inductor to ground, a secondary inductor mounted on said core, an amplifier having first, second and third control elements, a pair of conductors connecting the ends of said secondary inductor to the first element of said amplifier, one-way conductive devices in each of said conductors, means connecting said secondary induc-v tor intermediate the ends thereof to the second element of said amplifier, means connecting said source to the second'element of said amplifier, a plurality of electrically actuable fuel valves, means connecting the third element' of said amplifier to said valves, and means for successivel'y connecting said valves to ground in timed relation to said second mentioned means.

5. A fuel supply system control for an engine having aplurality of electrically actuable fuel valves comprising a core, primary and secondary inductors wound on said core, means synchronized with said engine for periodically'causi'ng current to flow in said primary inductor in alternate directions, means responsive to an engine operating condition for varying the intensity of current flow in said'prim'ary inductor and thereby the time duration that current is induced in said secondary inductor, an amplifier having first, second and third control elements, means connecting the first element to said secondary inductor intermediate the ends thereof, means including one-way conductive devices connecting the ends of the secondary inductor to the second control element, and means for successively connecting the third element to said valves in timedrelatio'n to said first mentioned means.

References Cited in the file of this patent UNITED STATES PATENTS 1,679,158 French July 31, 1928 2,115,298; Gunn Apr. 19, 1938 2,794,165 Scoyoc May 23, 1957 UNITED STATES PATENT OF F ICE CERTIFICATE OF CORRECTION Patent No, 2 92-7i 567 March 8! 1960 David C9 Breeding It is hereby certified that error appears in the -pri.nted specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Solumn 4 line 7 for "inductor wixrufling read 2 i,mldctdr KARL HG AXLINE ROBERT C. WATSON Aitesting @fiicer Commissioner of Patents UNITED STATES PATENT oTTTcT; CEEHHQATE U Q0 Patent Nos 232L567 March S 1960 David Co Breeding It is hereb$ certified that error appears in theprinted specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column. 4

line 7,, for "inductor winding incluctor read Signed and sealed this 18th day of Qatober 1960.,

Commissioner of Patents 

